I get that its used for a lot of good, which is great, and I've readily supported friends in the past who were raising funds for charity etc. But recently I've seen some rather dubious fundraising attempts which have left me thinking 
The one I've just seen is for a "homeless" soldier who has had his bedsit broken into. The thieves took his "Apple Mac" laptop which had precious photos of his time as a soldier. This person has raised over £800 so far.
Other one I saw was a guy who wasn't eligible for a maintenance style grant to study away from home. So was asking for help to pay for his accommodation.
I'm being cynical unreasonable, aren't I? Obviously each to their own and all that.